The present invention generally pertains to integrated circuit chips for electronic data processing systems and is particularly directed to preventing inspection of secret data that is stored in a secure memory element of the integrated circuit chip.
Integrated circuit chips that process and store secret data include secure memory elements that store the secret data. Typically the chips are encapsulated in a layer of opaque material that prevents inspection of the stored secret data by visual inspection techniques, such as scanning electron microscopy and mechanical probing. However, although removal of the encapsulation layer is difficult to accmoplish and typically requires the use of hazardous chemical, such as highly reactive solvents and acids, it is possible to remove the encapsulation layer without also damaging the remainder of the chip, and without disrupting any essential power connections to the secure memory elements, and thereby expose the secure memory elements of an integrated circuit chip to visual inspection.